The present invention relates to a valve on a processing plant in the chemical equipment field, as well as to a use of such a valve.
In the chemical equipment field, particularly in processing plants for products of the chemical or pharmaceutical industries, particularly high cleanness demands are made with respect to those parts of the plant coming into direct contact with the product, e.g. in connection with the sterility thereof. It is particularly difficult to fulfil this requirement on complicated mechanical parts, such as e.g. on valves. It is relatively easy for contaminants to pass from the outside on to the inner walls of the plant and consequently on to the product via adjustment elements for said valves or shaft packings. Another requirement, which is often difficult to fulfil on critical plant parts is the desired freedom from particles of the product and this must be ensured to a very high degree. This means that substantially no particles must pass from parts of the plant into the product, so that the high cleanness and therefore effectiveness thereof and possible its sterility are ensured.
In order to fulfil this first requirement, those parts of the plant coming into contact with the product have to be sterilised after processing a certain number of charges. According to the prior art for the purposes of sterilising the plant parts, it is on the one hand necessary to correspondingly and generally manually treat the accessible inner area and on the other hand complicated and in particular fissured parts of the plant are removed, separately cleaned, sterilised and then installed again. Particular attention must be paid to the seals or packings on the valve, because they are made form elastic material, e.g. an elastomer. These valve packings are subject to abrasion, so that on the one hand they can prejudice the required freedom from particles of the product and on the other it is in certain circumstances impossible to sufficiently reliably ensure the necessary sealing action. Therefore particular care must be taken in connection with the construction, so that the following charges satisfy the necessary requirements. If this does not occur, the following charges would be spoiled, which would lead to considerable economic and financial losses. Finally, the design of known valves based on technical circumstances alway gives rise to objections with respect to that area of the valve housing used for discharging the product, because the latter can only inadequately be removed from the housing, so that further problems occur during the cleaning and/or sterilisation process.